Flicker of LCD (Liquid Crystal Display) is generated by a variety of reasons, of which the most important reason is difference leakage of a TFT (Thin Film Transistor), because of the leakage of the TFT applying negative gray scale voltage is bigger than the leakage applying positive gray scale voltage, difference of a capacity is formed when the storage capacitor of the array substrate applying the positive and negative gray scale voltage. As the LCDs are now widely used in various fields, for reducing power consumption, the LCD is often applied a lower source drive voltage, so that the gray scale voltage difference between the adjacent gray scales is lower, the flicker generated is aggravating and affect the display.